We are constantly looking to employ new methods to enhance the separation and identification of peptides. We are fortunate to have Dr. David Goodlett as a core director as he is actively involved in the development of new mass spectrometry techniques (please see his biosketch and letter). We have also recruited an internationally recognized expert on mass spectrometry and bioinformatics, Dr. Timothy Veenstra, as an external consultant. These two individuals will insure that Core C provides state of the art advances to our end users. One future direction will involve incorporating stable isotope labeling methods, e.g. isotope coded affinity tag (ICAT) or iTRAQ methods, as well as so-called label-free methods as recently described in Dr. Goodlett's laboratory (Foss et al., In Press, Nature Genetics). This will allow us to provide information on the relative levels of expression of proteins in a complex and discern bona fide members of the complexes from non-specific, contaminating proteins58. In addition, depending on our resources, it may be possible to provide global proteome analysis as we previously described for mouse cortical neurons57 and mouse astrocytes (McBee et al, In Press, Proteomics;see Morrison Biosketch).